1. Field of the Invention
The present invention is generally related to a passive occupant detection system for a watercraft and, more particularly, to a tetherless safety switch that deactivates a marine propulsion system in the event that the operator of a marine vessel is not present at a preselected location.
2. Description of the Prior Art
Many different types of occupant detection systems are known to those skilled in the art. These systems have been used in automobiles and in conjunction with marine vessels.
U.S. Pat. No. 4,839,478, which issued to Howard on Jun. 13, 1989, describes a push button safety switch. A pair of switch terminals are mounted within a housing which also carries a plunger for movement relative to the housing. The plunger is biased for movement along a path of travel by a compressed spring. A push button actuator has a knob for contact by user and a plunger actuator carried by the knob. The actuator also defines a stem portion to support a tether clip coupled to the boat operator. The boat motor ignition circuit is electrically connected to the switch terminals and the motor can be deactivated by either user contact with the knob or through movement of the plunger initiated by separation of the tether clip from the push button actuator.
U.S. Pat. No. 5,330,226, which issued to Gentry et al on Jul. 19, 1994, describes a method and apparatus for detecting an out of position occupant. The apparatus for controlling the actuation of a vehicle occupant restraint system includes a displacement center mounted to the vehicle dashboard for sensing the distance between the: air bag storage location and the occupant in a seat. An infrared sensor is mounted in the headliner above the occupant. The infrared sensor has a plurality of viewing fields for sensing the location of the occupant relative to the air bag storage location and provides an output indicative of the occupant""s location relative to the air bag storage location. A controller determines the distance between the occupant and the air bag storage location from the output of the infrared sensor. The controller is also connected to the displacement sensor. The controller provides an electric enable signal when at least one of the sensors indicates that the occupant is at least a predetermined distance from the air bag storage location.
U.S. Pat. No. 5,525,843, which issued to Howing on Jun. 11, 1996, describes a seat occupant detection system. A method and system for detecting the presence of an occupant on a vehicle seat is described. The vehicle seat is provided with at least a pair of electrodes which are connected to a detection circuit for detecting a change in capacitance between the electrodes. If the detection circuit detects a significantly large change in capacitance, a positive detection signal is produced. To reduce the risk of interference, the electrodes of the detection circuit are substantially insulated from the chassis of the vehicle and its electrical system when the detection system is in an active condition.
U.S. Pat. No. 5,653,462, which issued to Breed et al on Aug. 5, 1997, describes a vehicle occupant position and velocity sensor. The sensor utilizes either ultrasonic, microwave, or optical technologies, or seatbelt spool out and seat position sensors. These are used as inputs to the primary vehicle crash sensor circuit to allow the longest possible sensing time before the occupant gets proximate to the airbag and is in danger of being injured by the deploying airbag. The sensor further disables the inflatable restraint system if the occupant is in danger of being injured by the system deployment. Separate systems are used for the driver and passenger to permit the optimum decision to be made for each occupant.
U.S. Pat. No. 5,702,123, which issued to Takahashi et al on Dec. 30, 1997, describes an airbag apparatus for a passenger seat. The apparatus includes a first sensor for detecting an occupant seated in a passenger seat, a second sensor for detecting a state in which the occupant is approaching an instrument panel excluding a state in which the occupant put out his or her hands on the instrument panel, and a deployment controller for changing the control of deployment of an airbag when the occupant is detected by the first sensor and the state in which the occupant is approaching the instrument panel is detected by the second sensor.
U.S. Pat. No. 5,871,232, which issued to White on Feb. 16, 1999, describes an occupant position sensing system which incorporates first and second position sensors, wherein the first position sensor senses the distance to the surface of an object and a second position sensor senses the electric field influencing properties of the object for purposes of controlling the activation of a safety restraint system. In an exemplary system, the first position sensor incorporates either an infrared beam or an ultrasonic beam as the sensing element, and the second position sensor senses the capacitance of a plurality of electrodes for either disabling an air bag inflator if the combination of the first and second position measurements of an occupant is within a threshold, or for controlling a controllable air bag inflator.
U.S. Pat. No. 5,171,063, which issued to Stidd on Dec. 15, 1992, describes a boat captain""s helm chair which has a seat part which is movable forwardly and rearwardly relative to a support with a back rest that has a retaining member such that its forward movement is counteracted. The forward portion of the seat part is rounded relative to the remaining portion to provide a support for the user in both a sitting and semi-standing rearward leaning postural position. Side portions of the seat extend forwardly of its mid portion to prevent lateral movements of the user. A compressive distortion of the armrest is counteracted by a dense U-shaped shock absorber to prevent the distortion of the armrest from constant use.
U.S. Pat. No. 5,108,321, which issued to Nelson on Apr. 28, 1992, describes a motor boat with an auxiliary motor. A motor boat with auxiliary and main motors and having a transom with a pocket or recess constructed and arranged to receive and support an auxiliary outboard motor. The auxiliary motor is connected to a steering control in a helm control center which steers both the auxiliary and main motors. Preferably operating controls enable starting, tilting, and steering of boat motors and associated propulsion assemblies from the helm. Preferably, the operating controls include a cable carried in a sheathing attached to a steering wheel mounted in the helm control center and adapted to turn or move the rudder of the main motor and the auxiliary motor propulsion assembly to thereby steer the boat.
U.S. Pat. No. 4,092,754, which issued to Yost on Jun. 6, 1978, describes a boat interior and cabin design. A hull is provided defining longitudinal upstanding opposite sides interconnected by a bottom extending between lower marginal edges of the side and by a bow structure at their forward ends and a transom structure at their rear ends. A pair of spaced apart midship opposite side compartments are provided immediately inwardly of the sides and define a center longitudinal aisle therebetween. A helm is disposed immediately rearward of one of the compartments and the sides terminate upwardly in generally horizontal gunwales. The compartments project upwardly appreciably above the gunwales and include forward upper portions inclined forwardly and downwardly toward the gunwales.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
Unlike automotive applications, marine applications of propulsion systems must consider the possibility that the operator of the marine vessel may attempt to move away from the operator seat or control location at the helm while the marine vessel is being operated. This may occur voluntarily or inadvertently. In certain accident scenarios, the operator of the marine vessel may be thrown from the boat or watercraft while the marine propulsion system, such as an outboard motor or outboard engine or stem drive system or a conventional inboard system, remains in an operative condition. It is important to provide some type of occupant detection system that can disable the marine propulsion system under certain conditions if the operator of the marine vessel leaves a preselected position at the control station near the helm. However, tethers can be cumbersome and require positive action by the operator in order to operate properly.
It would therefore be significantly beneficial if a tetherless and passive occupant detection system could be provided for a watercraft, such as a boat so that the operator""s action is not necessary.
An occupant sensing system for a watercraft made in accordance with the present invention comprises a marine propulsion system attached to the watercraft and a control position where a vessel control mechanism is located for manipulation by an operator of the watercraft to control the operation of the marine propulsion system. The vessel control mechanism can be a steering wheel, a throttle and shift control handle, trim buttons, or an ignition switch. A sensor is directed toward the control position of the watercraft and has an output signal which is representative of a first preselected characteristic of the control position. The present invention further comprises a monitor circuit connected in signal communication with the sensor for deactivating the marine propulsion system in response to a second preselected characteristic of the output signal.
The first characteristic is typically the presence of a human being at a preselected location within the control position and the sensor can be an infrared sensor. The second preselected characteristic is a decrease in the magnitude of the output signal from the sensor. The monitor circuit is also connected in signal communication with a neutral switch in certain embodiments of the present invention, whereby the monitor circuit only deactivates the marine propulsion system when the neutral switch is in a position signifying that the marine propulsion system is either in forward or reverse gear. The monitor circuit is connected in signal communication with a start switch of the marine propulsion system in certain embodiments. The monitor circuit can comprise a portion of the circuit that provides a time delay of a preselected duration subsequent to the marine propulsion system initially being started, as represented by a preselected status of the start switch, during which the monitor circuit does not deactivate the marine propulsion system in response to the second preselected characteristic of the output signal. The monitor circuit, in certain embodiments of the present invention has a deactivation signal output which is representative of an occurrence of the second preselected characteristic of the output signal. The system of the present invention can further comprise an engine control unit connected in signal communication with the monitor circuit and with a component of the marine propulsion system, whereby the electrical signal deactivates the marine propulsion system by providing the deactivation signal to the engine control unit which, in turn, deactivates the marine propulsion system in response to receipt of the deactivation signal from the monitor circuit.
The control position can be a seat where the operator of the watercraft normally is located at during operation of the watercraft. The sensor can be mounted on a dashboard of the watercraft, on a throttle and shift control housing of the watercraft in a steering wheel hub, or under a dashboard of the watercraft. Alternatively, the sensor can be mounted at any convenient location where it can be directed toward a position where the operator of the marine vessel is expected to be during operation of the marine vessel with the gear selector in a forward or reverse position.